It is possible that today’s children could have a shorter life expectancy than their parents and grandparents. This shocking thought comes to mind because children are becoming increasingly overweight, with a corresponding increase in the incidence of chronic diseases such as diabetes and cardiovascular problems, which shorten life expectancy. This article will present some facts you should know about the prevalence of overweight in children, the resulting health effects, factors that are thought to be contributing to the problem, and finally what you, as an early childhood educator, can do to help prevent childhood overweight.
Overweight in children and adolescents is a result of prolonged positive energy imbalance. That is, the calories children consume exceed the calories they expend. The exact reason for this imbalance among children is not clear (Odgen, Flegal, Carroll & Johnson, 2002). However, these are the three factors making up the energy balance equation that determines children’s body weight: 1) Food intake, including sugar consumption, snacking habits, etc.; 2) Amount of physical activity; and 3) Resting energy expenditure.
Others have proposed additional factors, including genetic factors such as ethnicity, demographics such as family size and number of siblings, geographic location (area of the United States or rural versus urban), socioeconomic factors, educational levels of family, and even season of the year (Klesges, Shelton, & Klesges, 1993).
Body mass index (BMI) is a measure of weight in relation to height. BMI has been a well-established measure of overweight for adults and now is available for the screening of children through the use of special growth charts labeled BMI-for-Age. It is no longer recommended to label children as “obese”, but rather “overweight” or “at risk of overweight”, since “obese” is generally used to describe the amount of body fat, and BMI-for-Age does not detect the percentage of body fat. BMI-for-Age provides a practical and useful screening tool to identify childhood overweight because of its simplicity and low cost. However, caution must be used in interpreting the results because of varying growth rates and possible ethnic differences. It is calculated as follows:
Metric: BMI = weight (kg) / stature (cm) / stature (cm) x 10,000
English: BMI = weight (lb) / stature (in) / stature (in) x 703
The resulting BMI must then be plotted on growth charts for boys and girls ages two to 20. More information about using BMI-for-Age to screen for childhood overweight can be found at the Centers for Disease Control (CDC) website: http://www.cdc.gov/growthcharts.
Prevalence and Trends in Childhood Overweight
The incidence of childhood overweight is increasing, and the rate of increase is accelerating (Freedman, Srinivasan, Valdez, Williamson, & Berenson, 1997). According to the 1999-2000 data collection of the National Health and Nutrition Examination Survey (NHANES) as reported by Ogden, Flegal, Carroll, and Johnson (2002), the percentage of children ages six to 11 who are overweight as defined by being in >95th percentile of BMI-for-Age has risen to 15.3%. They also reported that by comparison, NHANES I (1971-1974) data found only 4% of children ages six-11 were overweight. If the “at risk of overweight” category of 85th to 95th percentile is included in this figure, the number increases to 30.3% of children studied. This increase is often called “dramatic” and “epidemic”, with the sharpest increases among boys, African-Americans, Hispanics, and those living in southern states (Strauss and Pollack, 2001). Children of lower socioeconomic status also tend to be heavier (Wolfe, Campbell, Frongillo, Haas, and Melnik, 1994).
Troiano and Flegal (1998) found little or no differences at the lower percentile distributions, but increasing differences at the higher percentile distributions. This means that the heaviest appear to be getting heavier faster, a trend also noted in adults (Freedman, Khan, Serdula, Galuska, & Dietz, 2002).
Problems Associated with Overweight in Children
Increased Disease Risk. Coinciding with the increase in percentage of overweight children and adolescents is the increase in disease. Diseases that were formerly thought of as adult diseases are becoming more common in children, particularly diabetes, hyperinsulinemia, dyslipidemias, hypertension, asthma, and sleep apnea. Other diseases related to childhood overweight include mental disorders and gallbladder disease.
Quality of Life. Psychosocial consequences of childhood overweight can be social discrimination, negative self-image, parental neglect, and behavioral and learning problems (CDC, 2003). A recent study involved a quality of life survey administered to obese children, normal weight children, and children with cancer receiving chemotherapy ages five to 18 (N = 106). Results showed that obese children and adolescents reported significantly lower health-related quality of life, comparable to children with cancer undergoing chemotherapy (Schwimmer, Burwinkle, and Varni (2003).
Nutritional Factors Affecting Childhood Overweight
Children’s Food Preferences. Children’s food preferences for fatty foods and sweets may play a role in childhood overweight. Food preferences appear to be established by the ages of two or three years of age, and change little over the next five years (Skinner, Carruth, Bounds, & Ziegler, 2002). They evaluated the food preferences of 70 child-and-mother pairs over a five-year period and found the most frequently liked foods were carbonated soda, sweets such as cookies and donuts, snack foods like popcorn, crackers and potato chips, and popular fast foods like French fries and pizza. Apples were the only fruit/vegetable in the top list of liked foods, and were liked by 68 of 70 children surveyed. Vegetables were liked by less than half of the children.
Sugar and Carbonated Beverage Consumption. Increasing consumption of added sugars, particularly carbonated beverages has been linked to the increase in childhood overweight. The prevalence of soft drink consumption increased 48% from 1977-1978 to 1994-1995, with the mean intake increasing from five fluid ounces to 12 fluid ounces (French, Lin and Guthrie, 2003). Most of these beverages were the regular, sweetened type rather than the diet or sugar-free type (Harnack, Stang, & Story 1999). For all ages, higher intakes of carbonated beverages resulted in higher mean energy intakes, lower protein intakes, and lower intakes of nutrients. Guthrie and Morton (2000) found that the total intake of added sugars to be about 18.9% of total energy (about 363 additional calories from sweeteners daily) for six to 11 year olds, greater than the recommended 6-10%. They found that children ages six to 11 get the highest percentage of added sugars from regular soft drinks (21.9%), followed by other sweets, such as candy, syrups, gelatin desserts (20.8%), sweetened grains, such as cookies and cakes (13.8%), and fruitades or drinks (13.4%). Taken together, these four categories make up about 70% of added sugars. Surprisingly, sweetened breakfast cereals provided only 7.9% of added sugars. As consumption of sugar-sweetened drinks increased, BMI-for-Age also increased, allowing a prediction of rise or fall in BMI over two years by measuring change in consumption of sugar-sweetened drinks (Ludwig, Peterson, & Gortmaker, 2001). They suggested that consumption of sugar-sweetened drinks promotes overweight more than other categories of food because compensation at subsequent meals after drinking liquids is less complete than after consuming an equivalent amount of solid food. Unfortunately, they found that carbonated soda was the most frequently liked food among children; with 100% indicating they liked it.
Breakfast Habits. The role of breakfast in improved learning has been established (Murphy et al. 1998). However, little is known about the role of breakfast and overweight, especially in children. Research conducted in Spain, Korea and the Czech Republic found varying results. In Spain, Rocandio and Arroyo (2000) found no significant relationship between the caloric percentage of breakfast and BMI in a small group of children (n=32). In France, Bellisle, Rolland-Cachera, Deheeger, and Guilloud-Bataille (1988) found no significant difference in total energy intake, but that overweight children ate less breakfast and more at dinner than their leaner peers did. In a more recent study, Kovariva, Vignerova, and Osancova (2002) found that about 63% of Czech children ages seven to 11 ate breakfast, and of those with higher body weight, fewer (54.1%) ate breakfast. Eating breakfast has beneficial effects on appetite, insulin resistance, and energy metabolism in adults, regardless of the foods eaten (Pereira et al. 2003). Most regular breakfast eaters are less likely to become obese or develop insulin resistance than irregular breakfast eaters. Whether this is true in children still needs to be established.
Meals Eaten Away from Home. Americans spent 47.5% of their total food expenditure on meals away from home in 1999, an increase of 24.8% since 1990 (Clauson, 2000). Many of these meals eaten away from home provide larger portions with corresponding larger amounts of fat and calories than recommended. One study found that although restaurant meals accounted for only 6% of all reported eating, the energy content of restaurant meals was 55% higher than the average energy intake of home-based eating occasions (Zoumas-Morse, Rock, Sobo, and Neuhouser, 2001). They summarized that children and adolescents consumed significantly more energy from fat and saturated fat when eating at a restaurant than at any other location. Taveras et al. (2003) supported these results, reporting that the proportion of children eating more than three servings per week of fried food away from home (fast food) more than doubled over a three-year period from 1996 to 1999, and that increasing fast food consumption was associated with increasing BMI in children ages nine to 14.
Fat and Energy Intake. The role of fat and energy intake of childhood overweight remains uncertain. According to the 2002 Dietary Reference Intakes of the National Academy of Sciences Food and Nutrition Board, estimated energy needs of a six-year-old boy range from a minimum of 1308 calories for a sedentary activity level to a maximum of 1997 calories for a very high level of activity. Gortmaker, Dietz, and Cheung (1990) reported NHANES data indicating no statistically significant change in energy intake for six- to eight-year-old children. In fact, a slight decrease in daily energy intake was noted during the periods 1971–1973 to 1976–1980 (about 200 calories per day at the 90th percentile), while at the same time the rate of obesity was increasing. They hypothesized that it is possible for the prevalence of obesity to increase even without increased energy intake, because of possible declines in lean body mass. However, other environmental forces that can cause energy imbalance may also be present because energy intake in excess of expenditure is still a requirement for weight gain.
Portion Size. Portion sizes have been increasing since the 1970s, and most marketplace portions are larger today than USDA standard servings (Young & Nestle, 2003). They found that most food products studied have increased the portion size at least by a factor of two or more. For example, a Coca-Cola™ bottle when introduced in 1916 was 6.5 ounces; today’s popular bottle is 20 ounces. A chocolate chip cookie today may weigh four ounces, about eight times the “standard serving” of 0.5 ounce.
Several studies have investigated whether these larger portion sizes cause increased consumption. It appears that most people, except for very young children, will eat more when offered more. Rolls, Engell, and Birch (2000) found that five-year-olds ate larger amounts when presented with larger portions, regardless of their sex, liking for the food, or height and weight.
Television Viewing and Childhood Overweight
Decreased Physical Activity. The National Academy of Sciences Food and Nutrition Board (2002) recommends one hour of moderately intense physical activity daily for both adults and children. Television viewing can reduce the time available for this amount of physical activity. TV viewing among children is thought to impact weight in several ways, but the most significant association is from decreased physical activity while viewing.
Video games are also a popular activity for children, but the energy expenditure associated with them is not significantly higher than TV viewing. In fact, Ridley and Olds (2001) found that the most popular video games were the ones with the lowest energy costs, usually the ones involving only rapid hand movements, and that the majority of children do not significantly increase their energy expenditure by playing video games.
Nutritional Influences. TV viewing may impact weight in ways other than decreased physical activity and decreased metabolic rate. Other possible mechanisms are the influence ofTV food commercials, possible increased snacking while viewing, and the influence of foods or food attitudes discussed or displayed during programs (Gortmaker, Dietz, & Cheung, 1990). For example, Byrd-Bredbenner, Grasso, and Finckenor (2001) studied the NRI (nutrition-related information) in prime-time television programs. In an analysis of programs viewed by 2-11 year olds during prime time (8:00 to 11:00 pm Monday through Saturday and 7:00 to 11:00 pm on Sunday), they found that the average viewer saw about 17 scenes containing nutrition-related information. About 40% of these were judged to have some negative content, including one example that portrayed binge eating as fun and humorous. They also found that slim oraverage weight actors were shown eating low nutrient density foods, including fats, sweets or alcohol, about half the time. This may send a message that it is possible to eat a high fat, high sugar or high calorie diet and remain slim and healthy, a dissonant message that may influence children.
Difficulties in Measurement. Although TV viewing is often considered as a risk factor for overweight, its impact is difficult to measure. It could be possible that being overweight results in increased TV viewing and is not the consequence of TV viewing (Robinson, 1998). Some researchers have demonstrated a significant association between adiposity and TV viewing, while others have found no relationship. In most cases, the associations have been small. Further complicating the question is the difficulty in accurately measuring TV viewing and physical activity.
Relationship to BMI. Saelens et al. (2002) found that TV viewing hours were significantly related to children’s BMI in children ages 6-12. However, other researchers have found contradictory results in three to four-year-old children (DuRant, Baranowski, Johnson, & Thompson, 1994) and in sixth and seventh grade girls (Robinson, Hammer, et al.1993). DuRant et al. found that although the three to four-year-olds who watched more television were less physically active, there was no evidence of increased adiposity. This study was unique because it did not rely on self-report, but rather on direct observation of the children’s activities. The short attention span of this age group to TV viewing may also have been a factor, since the longest median bout of TV viewing was only 15 minutes.
Conversely, Anderson, Crespo, Bartlett, Cheskin, and Pratt (1998) found that boys and girls who watched four or more hours ofTV per day had the highest BMIs, while children who watched less than one hour of TV per day had the lowest BMIs. Even though the role of TV viewing in the development of childhood overweight remains uncertain, several studies have indicated that interventions to reduce TV viewing time can reduce BMI (Robinson, 1999).
Treatment of childhood overweight requires multiple interventions to increase physical activity and decrease energy intake at home, in child care settings, and at school. The American Academy of Pediatrics (AAP) (2003) recommends determining and plotting BMI yearly to monitor weight trends, and limiting children’s TV viewing to two hours per day or less. They also recommend promotion of breast-feeding, a healthy diet, and increased unstructured physical activity. The AAP acknowledges that few studies on prevention of childhood overweight have been performed, but based on limited research, recommends the above because of the need to be proactive in addressing the problem of childhood overweight. See http://www.aap.org/policy/s100029.html further information. for
Since children may spend many hours in the child care setting each week, early childhood educators are in an excellent position to model health-promoting behaviors and create an environment that encourages a healthy weight. What can you do in the child care setting to help prevent childhood overweight? Encourage physical activity and discourage TV viewing or video game use. Encourage a healthful breakfast that includes some fruit and whole grain bread or cereal for fiber. Allow children’s appetite to govern how much they eat, avoid commenting on the amount of food consumed at meals or snacks. Provide healthy snacks in small portions. Since a preference for a new food develops slowly with repeated exposure, offer new foods for tasting. Limit sugary foods and soda. Juice should be limited to four to six ounces per day; instead, encourage calorie-free beverages like water. If your program provides opportunities to educate parents, provide recipes and quick tips for simple and healthful meals to prepare at home. Unless there are serious health problems, weight loss is not advised for overweight children. Instead the goal is to prevent weight gain, allowing the child to grow into their weight.
Judy K. Martin, MS, RD is the dietitian at Reedsburg Area Medical Center, Reedsburg, WI. The preceding article is based on research completed for her thesis for the master’s program in Nutritional Science from the University of Wisconsin-Stout in Menomonie, WI.
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